Chem P5 help!

[abrraza]

can any bdy tell that how to calculate conc. of acid.. in oct\nov 10 53 q2(a) ... thnx in advance

 

[zahraahmed]

check the marking scheme

 

[abrraza]

not mentioned cleary

 

[abrraza]

:Search: any tips .. how to prepare for this exam???

 

[WellWIshER]

guys guys!!!!.....if we get da gradient i standard from should we convert it into decimal form???

 

[mrpaudel]

its not necessary i think!! u can leave it in standard form...no need to convert it into decimals!!

 

[Youme&I]

can any bdy tell that how to calculate conc. of acid.. in oct\nov 10 53 q2(a) ... thnx in advance

In succinic acid there are 2 hydrogen atoms to react with the NaOh just as in the case of H2SO4.This is a weak acid as its organic.There wud b a 1:2 ratio between number of moles of NaOH and succinc acid respectively.
now to calculate the values of column D:
calculate number of moles of NaOH ie C=n/V therefore 0.1x(value in column B/1000)=n
since NaOH:succinic acid is 1:2 ratio so to calculate number of moles of succinic acid divide by 2
calculate concentration by C=n/V number of moles ^^/(10/1000) 10 cm3 because thts the volume of water layer

repeat the same steps for column E but take concentration of NaOH 0.02 nd in concentration of succinic acid volume shud be taken as 25cm3

 

[Merdons Wolfman]

dont know

 

[zarajay]

for any experiment, what description shall we give as to how the temperature is controlled?!

 

[princesszahra]

can u just clear ur question plz.

 

[zarajay]

Q)Describe how you would alter the method to investigate how the rate of reaction varies
with changing temperature.

A) (mark scheme)Candidate repeats the experiment keeping HCl constant and
varying the temperature
Description of how the temperature will be controlled is required

its in s02 p5

 

[beacon_of_light]

Each temperature will be controlled using a thermostatically controlled water bath ...

 

[zarajay]

thanks!

 

[beacon_of_light]

 

[Yangkisherpa]

for any experiment, what description shall we give as to how the temperature is controlled?!

I think u say u wud conduct d experiment in a thermally controlled environment and/or use thermometers to monitor d temperature changes in d experiment u nid to keep an eye on.

 

[abrraza]

can any bdy tell that how to calculate conc. of acid.. in oct\nov 10 53 q2(a) ... thnx in advance

In succinic acid there are 2 hydrogen atoms to react with the NaOh just as in the case of H2SO4.This is a weak acid as its organic.There wud b a 1:2 ratio between number of moles of NaOH and succinc acid respectively.
now to calculate the values of column D:
calculate number of moles of NaOH ie C=n/V therefore 0.1x(value in column B/1000)=n
since NaOH:succinic acid is 1:2 ratio so to calculate number of moles of succinic acid divide by 2
calculate concentration by C=n/V number of moles ^^/(10/1000) 10 cm3 because thts the volume of water layer

repeat the same steps for column E but take concentration of NaOH 0.02 nd in concentration of succinic acid volume shud be taken as 25cm3

can u calculate one value for an example.. i nearly got it.. and that ratio is still confusing..

 

[angel eyez]

guys c this qs plz
n/09 52 qs # 1) f)
in the marking scheme they have divided by the ACID moles...
why have they done this.....n y haven't they divide it by NAOH MOLES??

PLZ HELP PEOPLE N FAST....
M UNABLE TO PREPARE 4 MY CHEM P5

 

[abrraza]

yeah! me tooo.. no clear method for preparation ...

 

[AAestar]

How do you find the mass of copper on cathode for q.2 nov 08?

 

[AAestar]

guys c this qs plz
n/09 52 qs # 1) f)
in the marking scheme they have divided by the ACID moles...
why have they done this.....n y haven't they divide it by NAOH MOLES??

PLZ HELP PEOPLE N FAST....
M UNABLE TO PREPARE 4 MY CHEM P5

See,the question table is about monobasic and dibasic acids . H2SO4 and ethanedios are dibasic all others are monobasic. And so we have to make the volume constant and as for the concentration, we have to half the number for dibasic , meaning if we used 2.0 for HCl then for h2so4 we will take 1.0 m. I am in the process of working on it, still...